An Introduction to Philosophy, Second Edition

Created March 25, 2024 by Marc Skuster

Learning Objectives - On completing this chapter, you will be able to:

Summarize Cartesian dualism as a theory of mind and explain how it results in the “mind-body problem.”
Discuss and evaluate the logical behaviorist concept of mind, including the role of “dispositions” in this alternative to Cartesian dualism.
Explain and evaluate the brain-state identity theory of mind.
Compare and contrast functionalism as a theory of mind with logical behaviorism and the identity theory.
Define “property dualism” and explain how it is relates to “the problem of conscious experience.”

Some of the main questions for the philosophy of mind are metaphysical questions about the nature of minds and mental states. “What is the mind?” quickly proves to be too big a question. We might say that for a being to have a mind is just for it to have mental states like beliefs, desires, perceptions, memories, emotions, and so forth. And this leads us towards somewhat more tractable questions like “What is a belief (desire, memory, perception. . .)?”

The philosophy of mind has seen tremendous progress since Descartes proposed his dualist view of mind and body. Contemporary philosophical analyses of mental states and processes are among the key components of a rapidly emerging new science of mind. Philosophers of mind, along with cognitive psychologists, information scientists, and neuro-scientists have begun to work out detailed explanations of how our physical brains realize and carry out the functions of many mental states. In this chapter we will cover some of the progress philosophy of mind has contributed over the past century. As we will see by the end, some hard philosophical questions about the nature of mind persist.

Descartes’ Dualism

As with many topics, modern philosophy of mind begins with Descartes and soon moves on. Descartes’ dualism holds that the mind is composed of a fundamentally different kind of substance than the body. Bodies are composed of matter that exists in space and time, and behaves in accordance with laws of nature. Minds, however, are spiritual in nature according to Descartes. Their existence is not spatio-temporally bound, and unlike physical stuff, minds have free will.

The Mind-Body Problem

The critical faults in Descartes’ view were quickly spotted by Princess Elisabeth of Bohemia. The central problem lies in accounting for how the mind and the body can have any influence on each other. Clearly the physical world has effects on the mind, as when I perceive things. And it seems equally obvious that the mind has effects in the physical world, as when I act on my will. But if mind and body are so completely different, it is hard to see how this can happen at all. How does something that exists outside of space and time have any influence over the body that exists in space and time? How can the behavior of my causally determined body be influenced by a freely willing mind? The problem of mind/body interaction is a major stumbling block for Cartesian dualism about the mind and the body.

The full original text of Descartes’ correspondence with Princess Elisabeth includes some ornate literary flirtation in the first couple letters. By today’s standards, Descartes could be accused of sexual harassment for much of his flattery of Elisabeth. But the patronizing flattery pretty much disappears in later letters as Descartes comes to appreciate the seriousness of the Elisabeth’s incisively argued challenge. Elisabeth provides a brilliant illustration of how to deal most effectively with patronizing behavior whether it is of sexist variety or some other kind: just be competent and this will show that you deserve to be taken seriously.

Alternatives to Cartesian Dualism

Logical Behaviorism

Following Hume in the 18^th century, the philosophy of science takes a sharp empirical turn in the latter 19^th and early 20^th century. During this time, what is scientifically knowable is taken to be limited to what can be defined in observable terms. This puts the mind and psychological phenomena generally on epistemically shaky ground. Mental states like beliefs, desires, perceptions, and anxieties are not the sorts of things we can examine under a microscope. If all things knowable are supposed to be knowable through sense experience, then it begins to appear that minds and mental states are not knowable.

The logical behaviorism of Gilbert Ryle (1900-1976) is an attempt to salvage talk of minds and mental states and make such talk empirically acceptable. Mental terms like belief or fear can often be associated with observable behavior. Anger and fear, for instance, often seem to be observable. Suppose we identified the mental state of being angry with displaying angry behavior. On this proposal, anger just is stomping around, cursing a lot or generally throwing a fit. The obvious problem here is that some people can be angry without displaying it and some people, good actors for instance, can engage in convincingly angry behavior even though they aren’t really angry. Or to take another example, my desire for chocolate ice cream might be observable in my rummaging around in the freezer, or it might not be observable at all because the usual behaviors are checked by my (also unobservable) desire to shed a few pounds. So mental states like anger or many beliefs and desires sometimes show in terms of behaviors, but perhaps only under the rights sorts of conditions. To make mental states empirically respectable and yet avoid the obvious problems we’ve seen in identifying mental states with observable behaviors, Ryle proposed to analyze mental states as dispositions to behave.

We are disposed in one way or another when we would behave a certain way given certain conditions. The behavior is not the disposition itself, but a manifestation of the disposition. The disposition can be identified in terms of a certain kind of “if. . .then. . .” statement. To help get clear on the idea, consider simpler physical dispositions like solubility or flexibility. To say that a spring is flexible is not to say that it is currently flexed. It is rather to say that if you were to stress it in the right way, then it would absorb the force placed on it and bend. To say that sugar is soluble is not to say that it is dissolved. But it is to say that if you were to submerge it in water (under the right conditions), then it would go into solution. So dispositions are described in terms of stimulating conditions and responses or manifestations.

Ryle’s idea is that talk of mental states, like beliefs, desires, perceptions, or emotions can be fully explained as talk of very complex dispositions where the stimulating conditions and the manifestations are observable conditions and behaviors. So, my desire for chocolate ice cream might be understood as a complex disposition to exhibit behaviors like rummaging around in the freezer if I think I’ll find chocolate ice cream there, and I’m not too worried about my weight, and . . . . If this project works out, then we can understand talk of mental states in terms of empirically respectable stimulus-response dispositions.

The project of defining talk of mental states in terms of observable environmental stimuli and behavioral responses faces a number of difficult challenges though. We normally understand simple physical dispositions as being grounded in some further physical basis. Sugar is soluble in water because of its molecular structure, for instance. So we associate the disposition of solubility with a physical state of the sugar. In his eagerness to avoid positing unobservable mental states, Ryle wanted us to understand talk of dispositions merely as defining mental terms in terms of empirically respectable stimulus response “if. . then. . .” claims. He wanted to avoid positing any unobservable states of the brain, for instance, as the basis of mental dispositions. So Ryle’s talk of dispositions is limited to mere “if . . then . . .” without any appeal to underlying states of minds.

A second problem is that while we might be able to formulate plausible stimulus response conditionals for some mental state terms like fear or anger, in many cases the subtle links between stimulus and response that we might associate with a belief or a desire are simply too complex to allow for an analysis of the mental state talk in terms of observably defined disposition talk. What “if . . then . . .” claim, for instance, analyzes talk of my belief that my brother lives in Arizona?

A distinct problem, one that will continue to dog subsequent theories in the philosophy of mind, is the problem of conscious experience. However Ryle’s project worked out, we could imagine some kind of mindless robot that satisfies all of the relevant stimulus-response dispositions we associate with beliefs, desires, and emotions. And yet, by hypothesis, the mindless robot lacks any subjective conscious experience. When we think of our own case at least, our subjective conscious experience seems to be quite central to having a mind. This is an issue we will return to after a brief look at a few other 20^th century approaches to understanding the mind.

The Brain State Identity Theory

Ryle’s behaviorism attempts to make talk of mental states empirically respectable by defining mental terms in terms of observable conditions and behaviors. One concern raised about this approach was that mental state terms are to be understood entirely in terms of observable things going on outside the person. This seems to take the mind out of the person. There is no place in behaviorism for any account of our inner lives or even the notion that my beliefs and desires are in some sense in me or part of me.

The Brain State Identity Theory, most ably advanced by J. J. C. Smart (1920-2012), goes some ways towards remedying this apparent defect (though Ryle would not have counted it as a defect). The Brain State Identity Theory proposes that mental states are identical with brain states. Contrary to Descartes’ dualism, the Identity Theory takes mind to be a physical thing. Namely, it takes the mind to be identical with the brain. For this reason, we count the Identity Theory as a physicalist view of the mind.

According to the Identity theory, the belief that Obama was president of the USA in 2002 just is a certain neuro-chemical state of the brain. Note that a great many people share this belief. When we speak of the belief as a view about what is true, one that might be shared by many people, we are speaking of a belief type. My belief that Obama was the American president in 2002 is just one token of that shared belief type. This distinction between types and tokens is important to understanding what the identity theory says. The Identity Theory originally proposed that mental state types are identical with brain state types. So for you to have the mental property of believing that Obama was president of the USA in 2002 is just for your brain to have a certain specific neuro-chemical property. The identity theory holds that for anyone to have the belief that Obama was president in 2002 is just for them to have that same specific neuro-chemical property. A popular and plausible example of such mental state/brain state type identity was that pain just is C-fibers (a certain kind of neuron) firing.

We have scientific evidence that very roughly points in the direction for something like the Identity Theory. Cases of localized brain injuries indicate that different parts of the brain carry out different functions. People who suffer lesions in specific areas of the brain tend to find specific mental functions impaired while other functions are left perfectly intact. It is through analyzing such cases that we began to map areas of the brain according to the functions they perform.

In the Identity Theory we witness a significant point of intersection between the philosophy of mind and the science of mind. Philosophical speculation has given rise to a great many scientific hypotheses. Here we have an example of how this can happen. We have a theory about the metaphysical nature of mental states that turns out to be empirically testable. The Identity Theory says that mental state types are identical with brain state types. Types are properties, so this view tells us that all of your mental properties are physical properties of your brain. We have learned a great deal about how brains store and process information since this hypothesis was popular. The science of mind is not yet mature, but well past its infancy and the broad outlines of how brains work are more or less in place. What the science tells us is that different brains store and process the same information in very different ways. That is, the Identity Theory is wrong. My belief that Obama was president in 2002 involves many properties of my brain. But your belief that Obama was president in 2002 involves your brain having different properties.

Functionalism

Belief is the spring of action. We explain people’s actions in terms of their mental states. People do what they do because of what they believe, desire, fear, hope for, and so forth. The behaviorists were on to something in thinking about mental states in terms of dispositions. But recall that the behaviorists were looking for a way to analyze talk about mental states entirely in terms of observable things like behavior. They wanted to avoid positing unobservable things going on in the head. Talk of dispositions for the behaviorists was not talk of underlying and possibly unobservable brain states that give rise to behavior. Rather it was merely talk of tendencies that might allow us to understand mental state terms as synonymous with complex “if. . . then. . .” conditional statements. The behaviorists sought a way to avoid understanding mental terms as referring to unobservable things going on in the head. To many, taking the mental out of the head seemed a problematic feature of behaviorism. But this is just what behaviorists set out to do, understand talk of the mental in public, observable terms.

The functionalists would understand talk of mental dispositions differently. To have a mental disposition is not, by definition, just to satisfy a certain “if . . ., then. . .” claim. Rather, to be in a mental state is to be in some underlying state, perhaps unobservable, that fulfills a certain functional role. The molecular structure that makes the spring flexible might not be observable to us. But for the spring to be flexible, for it to have this disposition, is for it to be in some underlying state that makes the spring such that if we exert a force on it, it will bend and absorb that energy. We can call that underlying state that accounts for something having a disposition the causal basis of the disposition. With this idea in hand, we can mark a difference in how a behaviorist and a functionalist would understand the idea of a disposition. For the behaviorist, talking of mental states as dispositions does not involve the attribution of any causal basis, it only gives us a way of translating talk of the mental into talk of observable behavior by means of complicated “if . . ., then . . .” statements. For functionalism, on the other hand, talking of mental states as dispositions does involve attributing underlying causal base properties. To be in a mental state is to have some underlying causal basis for behaving in this way if these conditions are met, or behaving in that way if those conditions are met, etc.

Given this differing treatment of talk of mental dispositions, the functionalist avoids a problem we raised for behaviorism. We seem to understand what it means to believe that Obama was president in 2002. But if this mental state attribution is really just a shorthand way of expressing a complex behavioral disposition, then we ought to be able to fill in the associated “if . . then . . .” claim. But we can’t. So talk of mental states can’t simply be regarded as synonymous with talk of behavioral dispositions. Unlike the behaviorist, the functionalist is not trying to define away talk of the mental in terms of talk of observable behavior. The functionalist is happy to leave the mental in the head. Statements about behavioral dispositions don’t define mental terms for the functionalist, they rather provide a means for specifying what it is for an underlying brain state to realize, or be a causal basis for, a mental state type.

We were lead to functionalism by the idea that a given mental state might be realized by various different states in different brains. This suggests a physicalist interpretation of functionalism, a view that insists that mental states are realized by physical states. But note that functionalism needn’t be restricted in this way. Any state, physical or otherwise, can realize a mental state so long as it fulfills the appropriate role. Being guided by spirits in the appropriate way might, in principle, be the causal basis for having a certain mental disposition. So, strictly speaking, unlike the brain state identity theory, functionalism is not committed to physicalism, the view that the mental is ultimately physical. One could be a functionalist about mental states and a Cartesian dualist.

Consciousness and Property Dualism

While one could, in principle, be a functionalist and a Cartesian dualist, the intractable problem of mind/body interaction has lead scientists of the mind to reject Descartes’ substance dualism. The difficulty of understanding consciousness, however, has led some leading contemporary thinkers, notably David Chalmers (1966-) to another kind of dualism: property dualism. On this view, though the world consists of just one kind of stuff, matter, that stuff has fundamentally different kinds of properties including those we can regard as purely physical, like mass, charge, and so forth, and other kinds of properties, like consciousness, that are irreducibly mental. Let’s start by thinking about how consciousness is special and especially difficult to analyze in terms of physical properties.

Functionalism gives us a promising approach for understanding some kinds of mental states in terms of physical states fulfilling functional roles describable in terms of complex dispositions. According to functionalism, for me to believe that my cat is sleeping on the sofa only requires that my brain be in some state that plays an appropriate function role. I can’t specify the functional role completely, but it might include walking softly when I go to refill my tea, not playing loud music on the stereo, saying “no” if my wife asks me if the cat is outside, etc. The state of my brain that fulfills this mental functional role might be one that can be entirely specified in physical terms. It is just the state of having certain connections between networks of neurons activated in certain ways. With enough neurophysiology, we could completely describe this brain state in terms of physical chemical and electrical properties. A great many kinds of mental phenomena might yield completely to such functional explanation in purely physical terms. Scientists of the mind have already made tremendous progress at understanding memory, shape recognition, belief, and desire in terms of functional roles that could have purely physical bases. But then there is our subjective conscious experience, what it is like for me to perceive something, for instance, or how I experience desiring something, believing something, remembering something.

Consciousness does not yield to functional analysis in the same way. An interesting kind of thought experiment suggests that consciousness can’t be understood in purely functional terms or in terms of physical properties and processes at all. First we need to talk about zombies. The zombies we are familiar with from horror stories are easily recognizable. They walk in menacing dull witted ways in spite of broken legs and open wounds. They are the reanimated dead. This is not at all like philosophical zombies, the beings that populate philosophical zombie thought experiments in the philosophy of mind. The idea of a philosophical zombie is the idea of being that functions exactly like a conscious person in every observable respect. The only difference between a philosophical zombie and a normal person is that the philosophical zombie lacks conscious experience. Imagine a physical duplicate of yourself, a doppelganger that is molecule for molecule exactly like you and fully operational. It functions just like you, so it would give the same replies you would give to questions and the same responses to stimuli. It is just as subtly expressive as you in every conceivable way because it is functionally just like you. Your mother or your lover could never tell the difference. The only difference there is, is that the zombie lacks the conscious experiences that you have.

There is philosophical debate about whether such a being is metaphysically possible. There don’t appear to be any logical contradictions involved, but that may not settle the issue. However, if such a zombie is possible, this possibility would demonstrate something interesting. Since your zombie doppleganger is exactly like your conscious self in every physical and functional respect down to the atomic level, yet differs from you mentally because it lacks conscious experience, the mere possibility of such a being would show that whatever consciousness is, it can’t be understood in terms of functioning or the kinds of physical biochemical properties that ground your functioning (provide the causal bases for your various dispositions to behave).

Chalmers thinks philosophical zombies are possible, so consciousness can’t be understood purely in terms of physical properties or the functional processes they ground. He instead proposes that we understand some properties of minds, like consciousness, as fundamentally mental properties that are not reducible, even in principle, to physical properties. While no distinct kinds of non-physical substance is proposed, Chalmers is offering a kind of dualism we now call property dualism. Property dualism in the philosophy of mind is the view that among the primitive most fundamental properties of our world, there are both basically physical properties and basically mental properties.

Review and Study

Review Questions:

What is Descartes' dualist theory of mind and body?
What is the the central problem with Descartes' theory of mind?
How did empiricism and the development of science lead to Logical Behaviorism?
Why did Ryle propose to denote mental states as dispositions to behave?
What are the problems with Ryle's attempt to interpret talk about mental states and stimulus-response claims?
What is the problem of conscious experience and why is it a challenge to logical behaviorism?
Why is the Identity Theory called a "physicalist" theory of mind?
What sort of scientific evidence supports the Identity Theory of Mind?
How does science show that the Identity Theory of Mind is wrong?
What is the difference between the behaviorist understanding of talk about dispositions and the functionalist understanding of such talk?
How could a functionalist also be a physicalist? A Cartesian dualist?
What does it mean to say that "the Functionalist is happy to leave the mental in the head?
What is the point of the "philosophical zombie" thought experiment?
How is "property dualism" different than Cartesian dualism?

Names, Concepts, Terms

Substance Dualism
Princess Elisabeth of Bohemia
The Problem of mind/body Interaction
Logical Behaviorism
Gilbert Ryle
Dispositions
The Problem of Conscious Experience
J. J. C. Smart
The Brain State Identity Theory
Physicalism
Functionalism
Philosophical Zombie
Property Dualism
Consciousness

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